I used Carthage and at first tried to not expand past Sicily in the east. Instead, I took the worthless colonies in North Africa and Spain. This was challenging bc playing defense from Carthage City and in Sicily is rough. U can expect a steady flow of blue Romans landing armies at Thapsus and in Sicily. Also, Spain has merc units that are pretty historically accurate like Spanish mercenaries, barbarian spearmen, gallic cav, Rhodesian and Baeleric slingers. W a core of African spearmen, elephants, and Numidian and Carthaginian cavalry, the mercs from Spain and gaul make it historic which is cool. The units are not all that great to be honest, which makes it fun because Hannibal did so well against the Romans just because he was such a great general. So IMO playing as Carthage in this way makes the most interesting way to campaign. Also because it allows the AI time to build up Rome where they're tough to be at after the Marian reforms.